SHARE @ Advocate Health - Midwest - Scientific Day: The Effect of Calcium Carbonate on Labor Induction: A Pilot Study
 

Affiliations

Aurora Sinai Medical Center, Aurora UW Medical Group, Advocate Aurora Research Institute

Abstract

Background/Significance:

Since 1976, U.S. cesarean deliveries (CDs) have increased ~30%. While CDs can be lifesaving, they pose a greater maternal risk than vaginal delivery. Thus, there is great interest in the prevention of CDs. The most common indication for CD is labor dystocia. Calcium carbonate (CaCO3), or Tums, has gained popularity for off-label use to prevent labor dystocia based on anecdotal evidence only. As calcium may improve uterine contractility and carbonate may decrease lactic acid, we sought evidence on the potential of CaCO3 to prevent labor dystocia and decrease CD rates.

Purpose:

To inform sample size and explore any safety/protocol concerns for future studies, we piloted CaCO3 use during labor induction assessing (1) induction duration with oxytocin, (2) labor dystocia rate, (3) CD rate, and (4) maternal/neonatal safety.

Methods:

We conducted a quasi-experimental, single-site pilot study among English/Spanish-speaking pregnant adults who presented for labor induction. A prospective treatment group (n=50) was consented June-September 2024, received CaCO3 (500mg every 4 hours) plus standard-dose oxytocin, and completed a side effect survey. A randomly selected retrospective historical control group (n=200) who presented for induction between 2020-2022 and received standard-dose oxytocin alone was also identified. Data was collected from the EMR or survey and stored in REDCap. Frequencies with percentages and medians with interquartile ranges, as appropriate, were computed. Differences were assessed using Pearson chi-squared test of independence or Fisher’s exact, or Wilcoxon’s Rank Sum test, as appropriate. Two tailed p < 0.05 was statistically significant.

Results:

Gestational age, parity, and starting Bishop score were similar between groups. While induction duration with oxytocin was significantly longer in the prospective CaCO3 group (766 vs 553 mins, p=0.02), the labor dystocia rate was clinically lower, though not statistically significant (4% vs 11%, p=0.18). Similarly, the CD rate was clinically lower in the prospective group but not statistically significant (14% vs 22%, p=0.24). There were no differences in maternal/neonatal safety outcomes. The survey revealed most had no or mild side effects with CaCO3.

Conclusion:

Despite a longer induction time, clinically relevant differences were found for labor dystocia and CD rates. Our pilot study reveals no safety concerns and informs sample sizes for future studies, as further information is needed to detect meaningful differences regarding CaCO3 use.

Presentation Notes

Presented at Scientific Day; May 21, 2025; Park Ridge, IL.

Full Text of Presentation

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May 21st, 11:41 AM May 21st, 1:15 PM

The Effect of Calcium Carbonate on Labor Induction: A Pilot Study

Background/Significance:

Since 1976, U.S. cesarean deliveries (CDs) have increased ~30%. While CDs can be lifesaving, they pose a greater maternal risk than vaginal delivery. Thus, there is great interest in the prevention of CDs. The most common indication for CD is labor dystocia. Calcium carbonate (CaCO3), or Tums, has gained popularity for off-label use to prevent labor dystocia based on anecdotal evidence only. As calcium may improve uterine contractility and carbonate may decrease lactic acid, we sought evidence on the potential of CaCO3 to prevent labor dystocia and decrease CD rates.

Purpose:

To inform sample size and explore any safety/protocol concerns for future studies, we piloted CaCO3 use during labor induction assessing (1) induction duration with oxytocin, (2) labor dystocia rate, (3) CD rate, and (4) maternal/neonatal safety.

Methods:

We conducted a quasi-experimental, single-site pilot study among English/Spanish-speaking pregnant adults who presented for labor induction. A prospective treatment group (n=50) was consented June-September 2024, received CaCO3 (500mg every 4 hours) plus standard-dose oxytocin, and completed a side effect survey. A randomly selected retrospective historical control group (n=200) who presented for induction between 2020-2022 and received standard-dose oxytocin alone was also identified. Data was collected from the EMR or survey and stored in REDCap. Frequencies with percentages and medians with interquartile ranges, as appropriate, were computed. Differences were assessed using Pearson chi-squared test of independence or Fisher’s exact, or Wilcoxon’s Rank Sum test, as appropriate. Two tailed p < 0.05 was statistically significant.

Results:

Gestational age, parity, and starting Bishop score were similar between groups. While induction duration with oxytocin was significantly longer in the prospective CaCO3 group (766 vs 553 mins, p=0.02), the labor dystocia rate was clinically lower, though not statistically significant (4% vs 11%, p=0.18). Similarly, the CD rate was clinically lower in the prospective group but not statistically significant (14% vs 22%, p=0.24). There were no differences in maternal/neonatal safety outcomes. The survey revealed most had no or mild side effects with CaCO3.

Conclusion:

Despite a longer induction time, clinically relevant differences were found for labor dystocia and CD rates. Our pilot study reveals no safety concerns and informs sample sizes for future studies, as further information is needed to detect meaningful differences regarding CaCO3 use.

 

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